[Buildroot] [v1 0/4] [PATCH 0/3] Add support for Pi5

[Gaël PORTAY]

On Thu Nov 23, 2023 at 4:25 PM CET, Gaël PORTAY wrote:
> On Thu Nov 23, 2023 at 11:12 AM CET, Thomas Petazzoni wrote:
> > On Tue, 21 Nov 2023 20:34:44 +0100
> > Gaël PORTAY <gael.portay at rtone.fr> wrote:
> >
> > > The output boots fine and it runs getty on uart and virtual tty if it is
> > > built using the toolchain built by buildroot.
> > > 
> > > The output boots the kernel but the kernel cannot run the init process
> > > if it is built using the bootlin prebuilt toolchain. Something is broken
> > > due to the 16k MMU page-size :(
> >
> > I *think* this is expected. The Bootlin toolchains are built for the
> > default page size of 4KB, so the libc in those toolchains expects 4KB
> > pages, and this breaks if you mix it with code that was built for 16 KB
> > page size.
> >
>
> Okay. So it needs to ship multiple toolchains, one per page-size? Or
> maybe there is a compiler flag or whatsoever; I saw a linker flag. I
> know nothing about that for now. I need to dig in.
>
> BTW, I wonder how the Raspberry OS deals with an image working for both
> 4k and 16k in a single userland; maybe it is just a matter of toolchain.
>
> > > Question: the device-tree overlays are taken from the rpi-firmware; is
> > > there a plan to compile the one from the downstream kernel sources
> > > instead? by tweaking the linux.mk maybe?

I have just tested with the toolchain "Arm AArch64 12.2.rel1" and it
works! It is just a matter of toolchain.

Gaël